2 Answers
2

I think this post need an update for anyone looking for up-to-date information. With the patch 1.0.3, the upgrading cost of the Blacksmith as been greatly reduced.
That said, the Blacksmith tier unlock costs break down like this, still actual for 1.0.7 and 1.0.8:

Normals tiers

free

5,000 gold

6,000 gold

10,000 gold

Nightmare tiers

12,000 gold + 2 pages of blacksmithing

20,000 gold + 6 pages of blacksmithing

Hell tiers

22,000 gold + 4 pages of blacksmithing + 2 tomes of blacksmithing

30,000 gold + 6 tomes of blacksmithing

Inferno tiers

28,000 gold + 4 tomes of blacksmithing + 2 tomes of secrets

40,000 gold + 9 tomes of secrets

This puts maxing the blacksmith at a total of 173,000 gold and some cheap books.
Since there is not modification for the jeweler, to maximize both artisans, you need: